And I told you to be patientAnd I told you to be fineAnd I told you to be balancedAnd I told you to be kindAnd now all your love is wastedAnd then who the hell was I?And I'm breaking at the britchesAnd at the end of all your lines

With Now all your love is wasted, Vernon is expressing regret at requesting so much support from his current girlfriend, while being unable to support her in exchange. Afterwards, he expresses the sentiment Who the hell am I to do that to someone?

With the last two lines, the imagery Vernon is going for is that his current girlfriend is keeping him part of the relationship by holding him up with ropes (lines), keeping him from falling completely away from her and into the pit of despair. But since he’s breaking at the britches, the whole effort that she is putting forth my be doomed to failure anyway.

Imagine he is dangling by his pants in a pit, with his girlfriend at the top trying to haul him up. She can’t haul him up herself, and he isn’t doing anything to help. His pants are starting to split, so if he doesn’t do something soon, he’ll fall despite her efforts.